Method or process of cementing pulp stones



Jan. 3, 1928.

1,655,371 H. o KEAY METHOD OR PROCESS Of CEMENTING PULP STONES Filed May 19, 1924 A PHENOLIC FORNALDBHYDERESIN IN FURI'URAL.

A PHENOUC FORMALDEHYDE RESIN IN FURFURAL 8; SAND INVENTUR HERBERTQKEAY 30 evenly.

Patented a... 3, 1928.

- UNITED. STATES. PATENT OFFICE.

HERBERT (KEAY, OF GRAND MERE, QUEBEC, CANADA, ASSIGNOR TO LAURENTIDE GOMPANY,-LIMI' 1ED, OF GRAND MERE, QUEBEC, CANADA.

I METHOD OR PROCESS OF CEMENTING PULP STONES.

Application flled liay I9, 1924. Serial No. 714,499.

This invention relates to a method or process ofcementing or bindingtogether two pulp stones of moderate thickness with an abrasive cement in order. to form a comparatively large stone-of suitable thickness for grinding pul wood in magazine grinders.

In the pro notion of pulp stones from sand stonequarries, considerable difiiculty is experienced in obtaining suflicient masses 'of clear sand-stone material, free from defects,

from which to turn out finished stones'suitable for grinding logs, such stones having, say, a finished diameter of sixty-two inches with a face width of fifty-four inches.

It is estimated that from twelve to fifteen stones of the same diameter, but of half the face width, could be turned out for every single stone of the larger face width of fiftyfour inches.

In order to produce a grinding stone by cementing or binding together two or more; stones of smaller. size, it is, obvious that the binding material must possess certain very important qualities It must, for instance, 2 be essentially insoluble'in hot water, must be a strong adhesive, must not crumble away in service, thus leaving a crack or opening or, in other words, it must contain an abrasive aggregate to do its part in grinding The binding material must, further, be sufliciently hard to re-inforce the edges of the stone so that crushing ofi' ofthe stone will not take place when the dressing burr is forced across the face of the stone. This binding material must, further, be sufficiently porous so that glazing will not take place at the grinding surface of the cement.

I have found that the above-mentioned qualities are obtained by using a resin dissolved in an organic solvent as a binder for an abrasive aggregate, For instance, I use a phenolic formaldehyde resin dissolved in 'furfural solvent for a binder, and sand as an abrasive aggregate, and this binder, when applied in the manner hereinafter described, produces a grinding stone possessing all the necessary requirements. The phenolic formaldehyde resin, is preferably such as set forth in British Patent No. 9291 of 1914 to Laurence Vincent Badman. Resins of this character are formed by incor orating hexarnethylenetetramine with a phenol and heatng the mixture, the excess of either reagent being removed or left in the compound as desired. Resins of this character may be manufactured b mixing the ingredients in suitable proportions to form a product which can be converted into an insoluble infusible chemically inert substance. The proportions are as' follows: one and one half phenol groups to one methylene group, or at least, nine molecules of phenol to one molecule of hexamethylenetetramine.

In the accompanying drawings, Figure 1 illustrates two stones with their adjacent surfaces prepared for cementing them together, and Figure 2 is a part sectional elevation of two stones cemented together ac-.

cording to my invent-ion.

In carrying out the process of cementing the stones together I first thoroughly coat the surface by any Suitable means, such as a stiff brush, with a solution of a henolic formaldehyde resin dissolved in urfural solvent. With ordinary sand-stones used for pulp grinding no further reliminary treatment of the surface is required, but if the sand-stone is exceptionally porous, I findit preferable to bake the stones after the preliminary coating has been applied. This baking treatment may be carried on for twenty-four to forty-eight hours at a temperature of approximately C. I then coat the surfaces to be cemented together with an abrasive cement which is made by mixing a fine clean sand with a suitable Quantity of a phenolic formaldehyde resin and to mixture is added a suitable amount oflfurfural solvent, the whole mass then being thoroughly mixed and kneaded until all the grains of sand are thoroughly moistened by the dissolved resin. sive cement is spread evenly to a depth of -about cne-sixteenth'of an inch over one, or

both, of the stone surfaces whichhave been previously coated, as above described. The

two surfaces are then pressed together firmly and clamped, for greater security in handling, while the cement is still plastic. The clamped stones are then placed in an oven and kept at a temperature of 130 to C. for approximately two days. The tem- This abra' tions. A phenolic formaldehyde resin or any similar artificial resin capable of solution by an organic solvent may be used in making this a rasive cement. As the abrasive cement constitutes the subject matter of another patent application filed by me it need not be specifically described in this application which is directed only to the process of cementing the stones together.

Having thus described my invention, what I claim is l. A process of cementing two or more stones together which consists in, first, coating'the surfaces to be cemented with a solution of a phenolic formaldehyde resin dissolved in an organic solvent, and then coating the prepared surfaces with an abrasive cement, clamping the stones together, then heating the stones for approximately forty-. eight hours to a temperature of 130 to 150.

C. and then increasing the heat to approximately 170 C. for a further period of twenty-four hours, then removing the stones and allowing same to cool.

2. A process of cementing two or more sand-stones together to form a pulp grinding stone which consists, in first, coating the surfaces to be cemented with a binder consisting of a phenolic formaldehyde resin dissolved in furfural solvent and then coating the treated surfaces with an abrasive cement consistin of fine sand mixed with phenolic formalde yde resin and furfural solvent,

then baking the cementedstones for approximately forty-eight hours at a temperature of 130 to 150 Cfand'then-increasmg the temperature to 170 C. for a further period of twenty-four hours.

3. A pulp grinding stone consisting of" several parts having their adjacent surfaces coated with a solution of a phenolic formaldehyde resin dissolved in an organic solvent and imited by a cement containing sand as an abrasive aggregate, said cement having the grinding qualities of the grinding stone.

4'. A pulp grinding stone consisting of several parts having their adjacent surfaces coated with a solution of a phenolic formaldehyde resin dissolved in an organic solvent and united by. acement consisting of fine sand mixed with a phenolic formaldehyde resin and furfural.

5. A pulp grinding stone consisting of several parts having their adjacent surfaces coated with a solution of a resin dissolved in an organic solvent and united by a cement .perature.

containing sand, a resin and an organic solvent.

6. The process of cementing twoor more stones together which consists in first, coating the surfaces to be cemented with a binder consisting of a resin dissolved in an organic solvent, then coating the so treated surfaces with an abrasive cement consisting of a mixture of sand, a resin, and an organic solvent and then baking the cemented stones.

7, The process of cementing two or more stones together which consists in first, coating the surfaces to be cemented with a binder consisting of a' resin dissolved in an organic solvent, then coating the, so treated surfaces with an abrasive cement consisting of a mixture of sand, a resin, and an organic solvent, thenbaking the cemented stones at a relatively high temperature and then subjecting the so baked stones to a further heat treatment at a higher temperature.

8. The process of cementing two or more stones together which consists in first,'coat ing the surfaces to be cemented with a phenolic formaldehyde resin dissolved in an organic solvent, then coating the so treated surfaces with an abrasive cement consisting of a mixture of sand, a phenolic formaldehyde resin and an 'organicsolvent, and then baking the cemented stones.

9. The process of cementing two or more stones together which consists in first, coating the surfaces to be cemented with a phenolic formaldehyde resin dissolved in furfural, then coating the ,so treated surfaces with an abrasive cement consisting of a mixtureof sand, a phenolic formaldehyde resin and furfural, and then baking the cemented stones.

10. The process of cementing two or more stones together which consists in first, coating the surfaces to be cemented with a phenolic formaldehyde resin dissolved in furfural, then coating the so treated surfaces with an abrasive cement consisting of a mixture of sand, a phenolic formaldehyde resin and furfural, then baking the cemented .stones at a relatively high temperature and then subjecting the .so baked stones to a further heat treatment at a higher tem- 11. A pulp grinding stone consisting of several parts having their adjacent surfaces cemented together with an abrasive-cement comprising sand as an abrasive element, said sand being mixed with a phenolic formaldehyde resin and furfural, the cement aggregate having thegrinding qualities of the stone which is united thereby.

12. A pulp grinding stone consisting of several parts of sand stone having their adjacent surfaces cemented together with an abrasive cement comprising sand as an abrasive element, said sand being mixed with a phenolic formaldehyde resin and fur fural the cement aggregate having the consisting of finesand mixed with a phegrin 'n qualities of the stone which is nolic formaldehyde resin and furfural, said 10 united thereby. cement aggregate having the grinding quali- 13. A pulp rinding stone consisting of ties of the sand stone itself. 5 several parts of sand stone having their ad- In witness whereof, I have hereunto set jacent surfaces coated with a solution of a my hand. phenolic formaldehyde resin dissolved in an organic solvent and united by a cement HERBERT O. KEAY. 

